Ontogeny of vocalization in duck and chick embryos.
D000818:Animals; D002642:Chick Embryo; D004372:Ducks; D004625:Embryo, Nonmammalian; D008566:Membranes / Q000196:embryology / Q000502:physiology*; D009132:Muscles / Q000502:physiology; D013045:Species Specificity; D013997:Time Factors; D014132:Trachea / Q000502:physiology; D014828:Vocalization, Animal